#include<iostream>
#include<string>
#include<vector>
#include<unordered_map>
using namespace std;

class Solution {
public:
    int minNumberOfFrogs(string croakOfFrogs) {
        string t = "croak";
        int n = t.size();
        vector<int> hash(n);

        unordered_map<char, int> index;
        for (int i = 0; i < n; i++)
        {
            index[t[i]] = i;
        }

        for (auto ch : croakOfFrogs)
        {
            if (ch == 'c')
            {
                if (hash[n - 1] != 0)
                {
                    hash[n - 1]--;
                }
                hash[0]++;
            }
            else
            {
                int i = index[ch];
                if (hash[i - 1] == 0)
                {
                    return -1;
                }
                hash[i - 1]--;
                hash[i]++;
            }
        }

        for (int i = 0; i < n - 1; i++)
        {
            if (hash[i] != 0)
            {
                return -1;
            }
        }

        return hash[n - 1];
    }
};

int main()
{
    return 0;
}